One of the medians of the triangle formed by the line pair and the line lies along the y-axis. If neitheranorris zero, prove thatbp+hq=0.

The line pair has its vertex at (0,0), so that is the vertex of the median on the y-axis. Then the midpoint of the intersection of the line pair and the line would be the other point on the median and triangle.

When x=0, on the line,

I found the sum of the points of intersection:

then

works out tohq-bp=0

I can't see where i have gone wrong.

Thanks